Method for relaxing keratinous fibres



Patented Mar. 16, 1948 UNH r METHOD FOR RELAXIN G KERATINOUS IBRE Edwin B. Michaels and Bernard Lustig, Stamford, Conn, assignors to Lawrence Richard Bruce, Incorporated, Stamford, Conn, a corporation of Connecticut No Drawing. Application January 18, 1944,

Serial N0. 518,774

'8 Claims. (Cl. 132-31) This invention relates to methods of relaxing keratinous fibresfor further treatment, such as cold permanent waving, and refers specifically to media for carrying out such relaxation.

By relaxation of keratinous fibres we mean that procedure wherein the fibre is afiected under treatment with the reagent so that the fibre passes from its normal state to a condition of rubber-like consistency, characterized by high plasticity, for example the fibre in such latter state can be readily deformed and caused to maintain that deformation permanently, upon subsequent treatments to destroy or remove the reagent. This rubbery state has been characterized by previous investigators as being dependent both upon the rupture of the constituent disulphide bonds of the keratinous material and to a high swelling of the material.

Of the reagents used in the past for the development of the above relaxing eifect, there were, for example, alkalis at a pH above 10, alkalis and reducing agents at a pH above 10, alkali sulphites and inorganic or alkali metal sulphides per se. The alkalis and alkali-reducing agents are characterized by so great a rate of reaction as to destroy the fibre and the normal sulphides at so low a rate as to be inefiicient for practical use. The alkali or metal sulphides which are applied at pHs above 9 provide an effective medium for initiating the relaxation of keratinous fibres, but have the notorious disadvantage of their toxic effect upon humans.

At the present time, bisulphites have been applied, as alkali bisulphites per se or in association with alcohol, and such media are relatively more efiicient than those previously discussed, except for the fact that the anion of such alkali bisulphites, per se, inhibit swelling of the fibre through the formation in solution of the di-valent S03 ion and thus reduce the speed of relaxation below the range required for permanent waving; while of such bisulphites are associated with alcohol through solution, the rate of reaction is increased, but the efficiency of the H503 anion, the active factor for causing swelling and relaxation of the fibre, is reduced by virtue of the fact that (a) the alcohol has a high vapour pressure,

so that, upon evaporation thereof as the treatment proceeds, the hair is cooled below optimum operating ranges; and (b) as the optimum pH range of an alkali bisulphite solution is the range at or about the pH of 5.5 and as an alkali bisulphite solution of this pH contains normal sodium sulphite and since normal sodium sulphite is insoluble in a solution of 40% alcohol, which is the optimum alcohol concentration for relaxation with bisulphites, it becomes impossible to obtain a bisulphite solution of optimum pH and H803 ion concentration in order to provide the required relaxing effect. This is due to precipitation of normal sodium sulphite from such a solution, which reduces the pH to about 4 and reduces thereby the bisulphite ion concentration in the solution.

We have ,found that by using water-soluble bisulphites having an organic cation and particularly containing a nitrogenous organic base of low molecular Weight, that (1) we have reduced the swelling-inhibition characteristics of the cation far below that of an inorganic or alkali cation; (2) we have maintained the H: structure of the anion, and this is an active swelling and relaxing agent as the bisulphite ionizes; and (3) We have found that this more highly relaxed state is attained through rupture of additional secondary valences by the organic cation and is not dependent upon further opening of the primary disulphite linkages of the keratin.

We have found that a reagent of the character of mono-ethanolamine-bisulphite incorporating a low molecular weight cation is the ideal reagent for swelling and relaxing keratinous fibre by virtue of an extreme solubility in water, high swelling power, high relative concentration of bisulphite ions, the absence of swelling-inhibiting cations, and the'presence of cations which rupture linkages within the protein structure to cause an additional swelling and relaxation.

.We have found, for example, that sodium bisulphite, as mentioned by Elsasser (see Patent No. 1,008,249) where the alkali cation has acted as a swelling-inhibitor, and that the sodium bisulphite solution has introduced unwanted SO: ions in solution through the following two-step dissociation reaction of the alkali bisulphite.

namely:

the dibasic S03 anion then serving as an inhibitor; and, further, I have found that the standard alkali bisulphite solutions normally incorporate impurities which introduce or act as swelling-inhibitors in solution, such as sulphate. chloride, bicarbonate, etc,

In order to eliminate the presence of nudesired inhibitors to the reaction of the; HSOa anion upon the disulphite bonds to produce relaxation, we have determined that it is essential to provide a cation which, in addition to its normal properties, has no inhibiting properties and represses the second dissociation of bisulphite ions which tive organic nitrogeneous base bisulphites is would normally form divalent sulphite ions. which 7 are, of themselves. swelling inhibitors.

Hsoaz=H++so=- We have found, for example, with respect to sodium bisulphite in alcohol. as mentioned by Speakman (see Patent No. 2,261,094), that although in Speakman's disclosure the alcohol acts as an ionization repressor and swelling agent directed towards the lessening of the tendency of the sodium bisulphite to form the divalent 80:: ions, it does not eliminate the presence of the swelling inhibiting alkali cation, it limits the solubility of the bisulphite at the optimum pH and, in addition to the physical disadvantage, by virtue of its low vapour pressure, of reducing the efllciency of the solution for permanent wave use, causes to an undesirable extent the fibres to become harsh and dry through the solvent effects of the alcohol.

By virtue, therefore, of our application of a reagent which incorporates a cation having little or no swelling inhibition, and in fact, a positive swelling effect, and since the anion is maintained in the form 1180:, the relaxing factor of the bisulphite, we provide for a consistent and positive swelling and relaxation of the fibre through rupture of both primary and secondary bonds of the keratin, Generally, reagents of the character thus outlined are classifiable in the group defined asbisulphites of mono-basic nitrogenous organic bases.

An example of one solution prepared according to this method is one prepared as follows: 10 grams of monoethanolamine is dissolved in 10 grams of water and S: is passed into the solution until a dilution of this solution containing by weight of S02 will have a pH of 5.5. The solution is used at the above dilution and pH and applied to the fibres between and C.. for example, for fifteen minutes at 35 C.

We have found that the optimum pH range for the reagents is between 5 and 6 and that the optimum SOs concentration is from 2 to 15%. We have found that whereas many reagents in this class show effective relaxing in the pH range 5-6, certain reagents, such as suanidine bisul- RHSO: where R represents a mono basic nitrogenous organic base containing one to eight carbon atoms, the bisulphite radical being attached to the nitrogen atom of the base; and all the compositions recited in the preceding paragraph are included in this general formulation. Among the specific formulations are the following: primary amine bisulphites of the formula RiNHaHSO: where R1 represents an organic radical containing 1 to 8 carbon atoms, as for example, any of the primary amine bisulphites specified in the preceding paragraph; primary amine bisulphites of the formula R'sNHsHSOa where R2 represents an alkyl radical containing 1 to 8 carbon atoms, as for example, methyl amine bisulphite; primary amine bisulphites of the formula RaNHaI-ISOe where R: represents an alkanol radical containing 1 to 8 carbon atoms, as, for example, :monoethanolamine bisulphite; secondary amine bisulphites of the formula RsRsNHzI-ISO: where R4 and R5 represent alkyl and alkanol radicals the sum of the carbon atoms of which does not exceed 8, as. for example, di-methyl amine and di-ethanolamine bisulphites; tertiary amine bisulphites. of the formula RcRIRsNHHSOa where R6, R1 and Rs represent alkyl or alkanol radicals, the sum of the carbon atoms of which does not exceed 8, as, for example, tri-methyl amine'and tri-ethanolamine bisulphites; the quaternary amine bisulphites of the formula RcRaoRuRmNI-ISO: where R9, R10, R11 and R12 represent alkyl or alkanol radicals, the sum of the carbon atoms of which does not exceed 8, as for example, the bisulphite of tetra-methyl ammonium hydroxide.

In general, it has been found that organic bases of a molecular weight as high as one hundred and fifty tend to be less effective unless the time or temperature of the reaction be extended to allow the larger molecules to gain access to the fibre. For this reason, my preferred reagents, particularly for application in permanent hair waving, are among the group having a relatively low molecular weight. Some of these compounds exhibit much greater swelling powers than others, as for example, the bisulphite compounds of the bases guanidine and amyl amine show two to four phite Show a much higher peak of reactivity at times greater swelling power than the'bisulphite the sharply defined pH of 5.8. The preferred pH range and the preferred S0: concentration, necessary to develop effective relaxation and swelling of the keratin, is attained in the class of bisulphites of mono-basic nitrogenous organic bases.

Following are representative organic nitrogen base bisulphites useful for effective swelling and relaxation of keratinous fibres: The primary amine bisulphites, such as bisulphites of methyl amine, ethyl amine, butyl amine, propyl amine, amyl amine, monoethanolamine, and aniline; the secondary amine bisulphites, such as bisulphites of di-methyl amine and di-ethanolamine; the tertiary amine bisulphites, such as bisulphites of trimethyl amine and tri-ethanolamine; the quaternary ammonium bisulphites, such as bisulphites of tetra-methyl ammonium hydroxide; the heterocyclic nitrogen base bisulphites, such as bisulphites of morpholine, pyridine and imidazole; the amidine bisulphites, such as bisulphites of guanidine and amino guanidine. The above bisulphites have been prepared and used at the specified pH and concentration for relaxing keratinous fibres along the lines of the above example.

compounds of methyl amine.

The relaxed fibre may be deformed and permanently set in its deformed state by the usual methods known to the art, such as the use of an oxidizing solution or the prolonged washing with water.

Various changes and modifications may be made to the details of the invention without departing from the broader spirit and scope thereof, as set forth in the following claims,

We claim:

l. The method of relaxing keratinous material which comprises treating the same at room temperatures with a water-soluble bisulphite, at a pH between 5 and 6, the cation of which contains a mono-basic nitrogenous organic base having swelling-increasing properties.

2. The method of treating keratinous material for permanent waving which comprises relaxing the sameat room temperatures with a watersoluble organic amine bisulphite at a pH between 5 and 6.

3. The method of relaxing keratinous material for permanent waving which comprises treating The general formulation for the representathe same at room temperatures with a solution of 5 monoethanolamine bisulphite, containing 240% S: at a pH of -6.

4. The method of relaxing keratinous material for permanent waving which comprises treating the same at room temperatures with a solution or guanidine bisulphite, containing 2-15% 80: at a pH of 5-6.

5. The method of relaxing keratinous material for permanent waving which comprises treating the same at room temperatures with a watersoluble bisulphite at a pH of 5-6 01 the formula RHSO: where R represents a mono-basic nitrogenous organic base containing 1 to 8 carbon atoms and the bisulphite radical is attached to the nitrogen atom of the base.

6. The method of relaxing keratinous material for permanent waving which comprises treating the same at room temperatures with a watersoluble primary amine bisulphite at a pH of 5-6 or the formula RiNHaHsoa where R1 represents an organic radical containing 1 to 8 carbon atoms.

7. The method oi! relaxing keratinous material which comprises treating the same at room temperatures with a water-soluble primary amine bisulphite at a pH oi 5-6 of the formula RzNHJHSO:

where R2 represents an alkyl radical containing 1 to 8 carbon atoms.

8. The method of relaxing keratinous material which comprises treating the same at room temperatures with a water-soluble primary amine bi- 6 sulphite at a pH of 5-6 of the formula RaNHsHSOs where R: represents an alkanol radical cOntalnlng 1 to 8 carbon atoms.

EDWIN B. MICHAELS. BERNARD LUSTIG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,155,178 Brown Apr. 18, 1939 2,310,687 Friedman et a1 Feb. 9, 1943 2,351,718 Speakman June 20, 1944 2,405,166 Reed Aug. 6, 1946 FOREIGN PATENTS Number Country Date 427,402 Great Britain Apr. 16, 1935 453,700 Great Britain Oct. 26, 1936 468,845 Great Britain July 13, 1937 472,745 Great Britain Sept, 29, 1937 117,730 Australia Nov. 18, 1943 OTHER REFERENCES Conn. Agr. Exp. Station, 46th Report Bulletin 460, May 1942, pages 448-450. Page 450 pertinent. 

